Power Systems Overview Quiz

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Questions and Answers

What are the primary sources of natural energy used in power systems?

Wind, gas, hydro, solar (correct)

Fossil fuels, renewable energy, nuclear

Nuclear, geothermal, biomass

Coal, oil, natural gas

What is the main function of an electric power system?

To convert natural energy to electrical energy and transport it to consumers (correct)

To convert electrical energy into other forms

To generate electricity from natural sources

To distribute electricity to consumers

Which of these is NOT a reason why electrical energy is preferred for transportation and control?

High power output (correct)

High efficiency

High reliability

Easy to transport

Which of these is NOT a basic requirement of a power system?

Capability to store large amounts of energy (B) Signup and view all the answers

What is the main reason for converting electrical energy into other forms?

To meet various energy needs of consumers (B) Signup and view all the answers

What are the main components of a power system?

Generation, Transmission, Distribution, Control Equipment, Load and Demand (A) Signup and view all the answers

Which of these is NOT a major factor contributing to the complexity of power systems?

Ideal generation units with constant voltage and frequency (C) Signup and view all the answers

What is the primary function of the governor in a power system?

Controlling the mechanical power output of the turbine (A) Signup and view all the answers

Which of these is NOT a typical source of power generation?

Light (B) Signup and view all the answers

What is the role of the distribution system in a power system?

Delivering electrical power to individual consumers (D) Signup and view all the answers

Why is the quality of electrical power important?

All of the above (D) Signup and view all the answers

What is the purpose of using a governor in an electrical power system?

To control the speed of the prime mover and maintain a constant frequency (D) Signup and view all the answers

What is the effect of driving uphill on the speed of the car?

Decreases the speed (B) Signup and view all the answers

What should the driver do to maintain a constant speed while driving uphill?

Increase the fuel setting (C) Signup and view all the answers

What is the primary advantage of operating multiple synchronous generators in parallel?

Improved reliability due to redundancy (D) Signup and view all the answers

What is the main function of the voltage regulator in a power system?

Regulating the reactive power output of the generator. (A) Signup and view all the answers

What is the primary function of the driver in this context?

To adjust the fuel setting based on road conditions (B) Signup and view all the answers

Which of these is a major challenge in power system operation?

The unpredictable nature of electrical load. (B) Signup and view all the answers

What is an 'infinite bus' in the context of power systems?

A power system with a very large number of generators connected together (B) Signup and view all the answers

Why is the storage of bulk electricity a challenge?

All of the above (D) Signup and view all the answers

What is the purpose of adjusting the fuel setting before reaching the desired speed when driving uphill?

To avoid overshooting the desired speed (A) Signup and view all the answers

In the analogy of driving a car, what does the car's accelerator correspond to in an electrical power system?

The governor (D) Signup and view all the answers

What is the primary objective of the governor feedback system?

To control the frequency and power output of generators. (D) Signup and view all the answers

What is the primary role of the AVR in a synchronous generator?

To control the field current and maintain terminal voltage (B) Signup and view all the answers

What happens to the load on the engine when the car is driving downhill?

Load decreases (D) Signup and view all the answers

What does the governor system do in a power system?

Controls the amount of fuel delivered to the turbine to maintain a desired speed. (D) Signup and view all the answers

What is the role of the feedback branch in a closed-loop control system?

It measures the speed of the turbine and sends a signal to the comparator. (B) Signup and view all the answers

How is turbine power output regulated in a power system?

By controlling the amount of fuel delivered to the turbine. (A) Signup and view all the answers

What happens when the turbine power output matches the electrical load on the system?

The net power balance becomes zero. (C) Signup and view all the answers

Why is the governor system described as a closed-loop control system?

Because it uses a feedback branch to adjust the fuel flow based on the desired speed. (D) Signup and view all the answers

What is the primary function of a governor in a turbine system?

To regulate the speed of the turbine by controlling the fuel supply (B) Signup and view all the answers

How does the valve in the turbine system respond to changes in turbine speed?

The valve closes when the turbine speed increases, restricting the flow of steam. (A) Signup and view all the answers

If the flyballs in the governor move outwards, what does this indicate?

The turbine speed is increasing. (D) Signup and view all the answers

What is the purpose of the 'droop' setting in a turbine-governor control system?

To allow for a small variation in turbine speed when load changes occur. (C) Signup and view all the answers

In a turbine-governor control system, what is the role of the controller?

To monitor the speed of the turbine and send a signal to the governor. (D) Signup and view all the answers

What is the difference between a 'speed reference' and a 'load reference' in a turbine-governor control system?

Speed reference is the desired speed of the turbine, while load reference is the desired load on the turbine. (A) Signup and view all the answers

What is the main function of the servomotor in a turbine-governor control system?

To adjust the valve opening based on the control signal. (C) Signup and view all the answers

What is the purpose of the exhaust flow in a turbine system?

To remove the waste heat generated during turbine operation. (B) Signup and view all the answers

Study Notes

Course Information

Course: ELEC 361 Power System Part 1_1
Instructor: Babak Nia
Office: KA 471-5
Email: [email protected]
Phone: (403) 210-4485

Power System Overview

Main function: convert natural energy to electrical energy, transport to consumption points
Natural energy sources: wind, gas, hydro, solar
Electrical energy is a convenient form for transport and control due to high efficiency and reliability
Most energy consumption is not initially electrical; electrical energy is converted to heat, light, and mechanical energy

Basic Requirements of Power System

Must satisfy continuous load changes (active and reactive power)
Cost and ecological impact are critical factors
Quality must meet minimum standards (constant voltage and frequency, high reliability)

Simple Power System Overview

Major components: generation, transmission system, distribution system, control equipment, load and demand
Components include power substation, high-voltage transmission lines, transformer, and power poles

Power System Components

Generation: power source (wind, coal, gas, hydro, solar) with specific voltage and frequency
Transmission system: a good conductor to transfer power from generation to loads
Distribution system: a good conductor network to transfer power to loads
Control equipment: measures system specifications to coordinate load and supply
Load and demand: power consumption by various equipment (lights, heaters, motors)

Why Power System is Complicated

Generation units/voltage sources are not ideal
Transmission system has inductance, resistance, and capacitance
Transmission systems have limited flow capacity
Load varies greatly throughout the day
Failure of any major component can cause system failure

Objective

Investigate the role of the governor feedback system on the control of frequency and power output of generating units in an interconnected power system

Frequency and Voltage Control

Components: Governor, Actuator, Turbine Valve, Turbine, AVR, Exciter, PT

Output Control

Governor controls the turbine's mechanical power output (real power -P) and maintains steady voltage output
Voltage regulator controls the excitation (reactive power -Q)
Device controlling frequency is the governor; device controlling terminal voltage is the AVR

Parallel Operation of Synchronous Generators

Necessary to feed large loads
Multiple generators provide reliability; more generators = higher reliability
Efficiency is higher when smaller generators are close to rated value (more efficient)
Large systems are called "infinite bus"

North American Interconnections

A map of North American interconnection areas

Why We Have to Use Governors

Electrical power source control is necessary
An uncontrolled power source with uncontrolled prime mover operates at undesired frequency and power
Governor is an attached device that provides automatic control of frequency

Simple Examples

Driving a car at constant speed requires controlling the accelerator (proportional to road slope)
Maintaining speed in different road conditions necessitates governor adjustments
Governor acts as a feedback system comparing desired speed to actual speed and adjusting accelerator

Governor and Driver

Governor is analogous to car driver adjusting to maintain desired speed (frequency)
Fuel adjustment is automatic
Governor is a closed-loop control system that brings sensor signals to a comparator
Comparator generates control signals for precise fuel adjustment

Power Balance

Governor-controlled valves regulate prime mover fluid flow to turbines
Turbine power output is proportional to valve position
Power output matches electrical load under steady conditions
Net power balance is zero; system maintains constant speed and frequency

Basic Mechanical-Governor

Components: fixed end, flyball, sliding collar, pivot, turbine, open valve area, exhaust

Photos of Governors

Pictures of various governors (historical and modern)

Valve Closed/Partially Open/Fully Open

Illustrations depicting different valve positions in a mechanical governor

James Watt's Steam Governor

Information and images about the historical steam governor design.

Turbine-Governor Control

Diagram illustrating the parts in a closed-loop control system that regulates turbine control based on load reference and speed reference

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Description

Test your knowledge on the primary sources of natural energy and the essential functions of electric power systems. This quiz covers the basic requirements, components, and complexities of power generation and distribution. Challenge yourself with questions about the roles of governors and the importance of electrical power quality.